The present invention relates to methods of forming a tissue scaffold.
The present invention is applicable to the formation of tissue scaffolds for any suitable use. For example, the tissue scaffolds formed may be used in forming replacement heart valves, vascular grafts, myocardial patches, respiratory and tracheal grafts, skin grafts or indeed any type of tissue graft. Similarly the invention could be used to engineer and produce scaffolds for the synthesis of any organ, partial or complete. Tissue scaffolds formed in accordance with any aspect of the present invention can be used for any tissue engineering/augmentation application such as vascular grafts, intestinal grafts, tracheal grafts, oesophageal grafts, etc, and may be combined with a stent, as described below, in certain applications.
The present invention in some preferred embodiments relates to the formation of a tissue scaffold for forming replacement heart valves. The current treatments for Heart Valve Replacement (HVR) are mechanical valves (metal or polymer) or bio-prosthetic valves from animal/deceased donor heart. In the latter type, cells and cellular debris are removed from the valve, leaving only the “scaffold” of the valve tissue. However, notwithstanding the surgical risks, there are still many problems associated with these types of HVRs. In the case of mechanical valves, they have the potential to undergo actual mechanical failure as they have a limited lifespan (8-10 years) and are prone to calcification/clotting. Furthermore, they produce an audible clicking sound in use which some patients are very conscious of. Although bio-prosthetic valves are made from a de-cellularised biological source, thus addressing some of the issues associated with mechanical valves, there is still a large risk of disease transfer and, more importantly, immuno-rejection of the implant by the patient. Both of these implant types are permanent implants as they are not resorbed by the body. As a result, new heart tissue formation and regeneration, if any, is therefore limited.
Although attempts have been made to engineer HVRs by electrospinning fibers to form artificial scaffolds, they have failed to generate scaffolds which adequately mimic the biological and mechanical properties of natural donor scaffolds from bio-prosthetic valves.
While some of the benefits of the present invention have been illustrated by reference to the context of engineering HVRs, it will be appreciated that the invention is not limited to this application, and provides similar benefits in the formation of tissue scaffolds for other purposes. For example, the methods of the present invention may produce tissue scaffolds for other applications, such as grafts or any other application as discussed above, which more closely mimic the biological and mechanical properties of natural e.g. donor scaffold structures.
The present invention attempts to overcome or mitigate the disadvantages of known techniques by providing novel methods for forming a tissue scaffold.